#!/bin/sh
# A shell script to maintain ChangeLog.txt

# Copyright 2018-2019 orbea
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# This is required for the legacy ash in Slackware and can be removed
# once ash is no longer included in any supported Slackware releases.
# shellcheck disable=SC2004
# https://github.com/koalaman/shellcheck/wiki/SC2004

TMP="${TMP:-/tmp}"

set -euf

branch="$(git rev-parse --abbrev-ref HEAD)"
origin=master
chlog=ChangeLog.txt

[ "$branch" = $origin ] && { printf %s\\n "Already on '$origin'."; exit 1; }
[ -f ./$chlog ] || { printf %s\\n "No '$chlog' found."; exit 1; }

trap 'rm -f -- "$TMP/$chlog.new"; trap - EXIT; exit 0' EXIT INT
mkdir -p -- "$TMP"
cat /dev/null > "$TMP/$chlog.new"

git log --format=%s "$branch" ^$origin --no-merges | while read -r line; do
  [ "${line}" ] || continue
  printf %s\\n "$line" >> "$TMP/$chlog.new"
done

date="$(date -u)"
day="$(date -u +%Y%m%d)"
tag=1

while git rev-parse "$day.$tag" >/dev/null 2>&1; do
  tag="$(($tag+1))"
done

sed -i '1s/^/+--------------------------+\n/' ./$chlog
sort < "$TMP/$chlog.new" | sed "1s/^/$date\\n/" |
  cat - ./$chlog > "$TMP/$chlog.tmp"
mv -- "$TMP/$chlog.tmp" ./$chlog

git add ./$chlog
git commit -sm "Public www update: $date."
git tag "$day.$tag"
